Plasma-generated coating apparatus for medical devices and a method of coating deposition

Abstract

An apparatus for plasma polymerize coating of medical devices, such as stents, is disclosed. A method for forming plasma-polymerized coating for implantable medical devices is also disclosed.

What is claimed is: 
     
       1. An apparatus to plasma coat a stent, comprising:
 a mandrel supporting a stent; 
 a first plasma member circumscribing the mandrel, the first plasma member being grounded and the mandrel being supported as a cantilever from the first plasma member; 
 a second plasma member circumscribing the first plasma member; 
 a plasma generating source in communication with the second plasma member; 
 a first horizontally disposed plate member in communication with the first plasma member; 
 a second horizontally disposed plate member positioned over the first plate member and in communication with the second plasma member; 
 a third plate member, wherein the second plate member is adjacent to, and in communication with a proximal end of the second plasma member and the third plate member is adjacent to, and in communication with a distal end of the second plasma member; and 
 an insulator disposed between the first and second plate members to electrically insulate the plate members; 
 wherein the mandrel extends from the first plate member into the first plasma member and through an opening formed in the second plate member. 
 
     
     
       2. The apparatus of  claim 1 , wherein the first plasma member is a first hollow tubular body in which the mandrel is positioned, and wherein the second plasma member is a second hollow tubular body in which the first hollow tubular body is positioned. 
     
     
       3. The apparatus of  claim 2 , wherein the first and second hollow tubular bodies include perforations. 
     
     
       4. The apparatus of  claim 2 , wherein the stent is positioned in the center of the first hollow tubular body. 
     
     
       5. The apparatus of  claim 1 , wherein the stent does not contact the first plasma member during the coating process. 
     
     
       6. The apparatus of  claim 1 , wherein the first plasma member is a hollow tubular body in which the mandrel is positioned and wherein the second plasma member is a coil element wrapped around the hollow tubular body. 
     
     
       7. The apparatus of  claim 1 , wherein the plasma generating source is a radio frequency generating source. 
     
     
       8. The apparatus of  claim 1 , wherein the plasma generating source generates gaseous plasma to modify a surface of the stent. 
     
     
       9. The apparatus of  claim 1 , wherein the plasma generating source generates gaseous plasma to form a polymer film on a surface of the stent. 
     
     
       10. The apparatus of  claim 9 , further comprising a plasma-polymerizable monomer that is in a gaseous form and is inside the second plasma member. 
     
     
       11. The apparatus of  claim 10 , further comprising a source that supplies the polymerizable monomer gas to the second plasma member. 
     
     
       12. The apparatus of  claim 1 , wherein the plasma generating source generates gaseous plasma to induce polymerization of a plasma-polymerizable monomer on a surface of the stent to form a polymer film. 
     
     
       13. The apparatus of  claim 12 , wherein the plasma-polymerizable monomer is in a gaseous form and is inside the second plasma member. 
     
     
       14. The apparatus of  claim 13 , further comprising a source that supplies the polymerizable monomer gas to the second plasma member. 
     
     
       15. The apparatus of  claim 1  wherein a substantial portion of the stent mandrel is disposed between the second and third plate members. 
     
     
       16. The apparatus of  claim 1 , wherein the mandrel is supported as a cantilever from an end of the first plasma member.